Agriculture currently utilizes fertilizers to deliver the needed nutrients of nitrogen, phosphorus, potassium, sulfur, calcium, and magnesium to plants through the application of fertilizers to the soil. Nitrogen generally is the most yield-limiting and costly nutrient element in crop production. Fertilizers are based on nitrogen content, mainly urea and additional plant nutrients and additives. Fertilizers can either be formulated as man-made products or natural organic based animal manure. Nitrogen is the primary nutrient in fertilizers and urea is the primary nitrogen source in fertilizers. Thus, fertilizers have become one vehicle for increasing the nitrogen content in the soil to assist in maintaining the health, overall quality, growth and yields of many of the plants important to agriculture and to civilization. Nitrogen is usually formulated into fertilizer by one or more of urea and/or ammonium nitrate and/or ammonium sulfate and/or manure and/or ammonium phosphate and/or the like.
Generally, the fertilizer is applied to the soil as either a liquid or a solid. Maintaining a sufficient level of nitrogen concentration in the soil proves difficult over time due to nitrogen and nitrogen containing compounds (such as urea) solubilities in water.
When rain or water run-off contacts the soil, the nitrogen or nitrogen containing compounds may be carried with the water to surrounding water-ways.
Alternatively, the degradation of nitrogen content may be attributed to volatilization (such as for ammonia and NOx where x is 1, 2 or 3) and water runoff due to the better water solubility of nitrites/nitrates. Loss due to volatilization is sometimes driven by a urease enzyme that catalyzes hydrolysis of urea to ammonia and carbon dioxide and to the biological oxidation by soil microbes, such as Nitrosomonas bacteria, of NH3 or NH4 to NOx's such as nitric oxide, an atmospheric greenhouse gas which, on a molecular basis, has 310 times the global warming potential of carbon dioxide. This results in a substantial loss of nitrogen content in the fertilizer impacting costs to the farmer. Moreover, the loss of nitrogen from the soil results not only in water pollution but also atmospheric pollution.
Nitrogen in the soil is also lost by the attack of nitrogen and nitrogen containing compounds (such as urea) by enzymes like the urease enzyme. Attack by the urease enzyme causes urea to degrade to carbon dioxide and ammonia. Biological oxidations by soil microbes, such as Nitrosomonas bacteria, of ammoniacal nitrogen to nitrate nitrogen are also a cause of the diminishing nitrogen content in soil over time. While the conversion of urea to ammonia and oxidation of ammonia to nitrates within the soil is beneficial to plants, conversions occurring on top of the soil, where fertilizers are applied, also results in a loss of nitrogen. To improve the longevity of nitrogen in the soil, fertilizers have been treated with nitrification inhibitors and urease inhibitors. These inhibitors are usually imparted onto the surface of fertilizer granules or added to liquid fertilizers through an aqueous solution.
Thus, it is desired that one increase the life expectancy of nitrogen in the soil to insure more consistent levels of nitrogen during the growing season while also decreasing the number of times the fertilizer is applied to the soil. Increasing the life expectancy of nitrogen in soil while simultaneously decreasing the number of applications of fertilizer will lower the overall cost to the agriculture industry while at the same time limiting the amount of nitrogen carried into the waterways. The present methods that are used create polluting conditions that are believed to have fueled the formation of the Gulf Dead Zone, the formation of toxic algal blooms as well as damage to drinking water supplies. Thus, finding delivery formulations that are safe for the environment and for animals and that contain the proper levels of nitrification inhibitors and/or urease inhibitors that may be applied directly to the soil in a liquid form or imparted onto fertilizer granules as a one-step application would be advantageous to the agricultural industry. Such a treated fertilizer would also assist in slowing two major biological processes that cause substantial loss of nitrogen in soil while simultaneously assisting in controlling pollution of our water and atmosphere.
Various methods as disclosed in the patents below, which are incorporated by reference in their entireties. These methods have been proposed and developed for controlling volatile nitrogen losses from urea.
Barth (U.S. Pat. No. 6,488,734) introduces the concept of the use of polyacids, which contain nitrification inhibitors, and pyrazole derivatives for the treatment of inorganic fertilizers;
Halpern (U.S. Pat. No. 5,106,984) shows how to prepare 1,1-dichloro-2-propanone and acrylonitrile by the formation and further reaction of 4,4-dichloro-5-oxo-hexanenitrile, which are utilized as herbicides and as a nitrification inhibitor.
Evrard (U.S. Pat. No. 4,294,604) discloses the use of selected N-(2,6-dimethylphenyl)-alanine methyl ester compounds as ammonium nitrification inhibitors.
Michaud (U.S. Pat. No. 4,234,332) describes aqueous solutions of commonly used fertilizers which also contain dicyandiamide, in an amount to provide at least 10% by weight of dicyandiamide nitrogen which is an effective nitrification inhibitor.
Sutton et al. (U.S. Pat. No. 5,024,689) teach the use of liquid fertilizer that includes urease inhibitors such as NBPT and nitrification inhibitor such as dicyandiamide in aqueous mixtures of urea, ammonium polyphosphate, ammonium thiosulfate and potentially other plant growth improving compounds.
Sutton (U.S. Pat. No. 8,562,711) provides a method for developing a dry, flowable additive for aqueous urea-based fertilizers based on solid urea formaldehyde polymer, N-(n-butyl) thiophosphoric triamide, and, optionally, dicyandiamide that imparts reduced nitrogen loss from the soil. Also, Sutton provides that the dry additive may be blended with molten or solid urea to form a solid urea-based fertilizer with reduced nitrogen loss from the soil.
While many of these techniques have a positive impact of maintaining the level of nitrogen in the soil, they also have significant problems. For example, problems that have adversely affected the agricultural industry include costs of improvement, loss of viability upon storage, and the inability to deliver consistent levels of fertilizer due to poor coating of the inhibitors or clumping of granules. Some innovations utilize aqueous delivery systems to granular fertilizer. However, aqueous delivery systems not only cause fertilizer to clump, but if this fertilizer has also been coated with an alkyl thiophosphoric triamide such as nBTP, the presence of moisture will cause degradation of the alkyl thiophosphoric triamide. Other techniques utilize adding DCD powder to other solids, which is costly due to major fertilizer producers' processes for are continuous and not batch operations. Thus, there is a need for a non-aqueous liquid formulation containing a nitrification inhibitor, which addresses many of the shortcomings discussed above providing more flexibility for fertilizer manufactures to produce products designed to the soil requirement in different regions of the world.